Operating a fleet of long-haul trucks in the most cost-efficient manner has been and remains a goal of many truck owners and companies. The owner of the trucks tries to keep costs at a minimum while providing good service and product delivery for the customers. Among the costs the owner tries to keep at a minimum are the costs of fuel, engine maintenance and replacement, etc.
When the driver is not the owner, he often does not pay for the fuel and therefore is not concerned with the cost of the fuel in driving the truck from one location to another on a long haul. The driver often drives at excessively high speeds, which not only uses excess fuel but also is dangerous. The owner would like governors on the truck to provide fuel-efficient and safe operation.
Many different methods and machines to achieve the goal of fuel-efficient and safe long-haul truck operation have been tried in the past.
Patents have issued which describe various types of governing systems for a large engine; for example, U.S. Pat. Nos. 4,515,040; 4,484,555; 4,448,094; 4,445,329; 4,439,833; 4,416,230; 4,351,293; 4,076,094; 3,948,116; 4,422,420; 4,248,194 and 3,890,360. These patents describe various systems for engines or transmissions in trucks. For example, U.S. Pat. No. 4,515,040 describes the use of a continuously variable transmission to bring the engine torque and the engine revolution speed to desired target values. U.S. Pat. No. 4,448,094 describes use of a governor that establishes a maximum rpm for the engine when air pressure is supplied to the governor and a lower maximum rpm for the engine when the supply of air to the governor is interrupted. The lower rpm range of the governor is engaged when the transmission of the vehicle is in a preselected gear. U.S. Pat. No. 4,416,230 describes a fuel cutout control circuit which terminates delivery of fuel to the engine when the throttle valve opens at an angle less than a predetermined value and the transmission is in high gear or in neutral. Pat. No. 4,351,293 describes a speed control system for a diesel-powered vehicle in which a sensing element responsive to the speed of the vehicle is connected through a control to close the fuel supply to the diesel engine to permit a preset limitation on vehicle speed. Similarly, U.S. Pat. Nos. 4,076,094 and 3,948,116 describe devices to limit the speed of the engine in response to vehicle speed, depending on the transmission gear of the vehicle. U.S. Pat. No. 4,422,420, to Cromas et al., describes a dual fuel flow path to provide fuel to the engine. An advertisement by TRW Inc., the assignee of the Cromas et al. patent, states that the system precisely controls the vehicle's road speed to established limits and a feature limits top engine speed in all gears. Similar advertisements by Hewitt Industries and Sturdy, Controls Division, describe features of engine control systems.
U.S. Pat. No. 3,948,116, to van Pelt, describes a governor to regulate the supply of fuel, with the supply of fuel being less when the top gear is selected. Column 1, lines 60-65, states that in the lower gears, the governor is ineffective so that the vehicle can be accelerated to a maximum. However, as soon as the top gear is engaged, the adjusting means are operated such that the maximum engine speed obtainable is lower than in the lower gears. Features similar to those discussed in the patent to van Pelt are also described in other patents, such as those to Katayose et al. and Yarnell, respectively U.S. Pat. Nos. 4,416,230 and 4,448,094.